Magnetic-Base Indicator Holder, Arm Type Rigid, Base Height 2 3/8 in, Base Length 3 in, Base Size 3 in L x 2.375 in W x 2.375 in H, Base Type Magnetic, Base Width 2 3/8 in, Compatible Indicator Mounts Lug-on-Back, Fine Adjustment Position Fine Adjust Top (FAT), Holding Power 150 lbf, Maximum Reach 15 in, Step Type V Step, Working Length of Post/Lower Arm 9.375 in, Working Length of Snug/Third Arm 1 in, Working Length of Upper Arm 9.375 in, Base Thread Size 1/4 in-20, Construction Cast Iron